Among flat panel display technologies, Thin Film Transistor (TFT) Liquid Crystal Displays (LCDs) have the traits of low power consumption, relatively low manufacturing cost and being irradiation-free, and thus play a leading role in the market for flat panel displays. In a peripheral portion of the TFT array substrate surroundings its portion to be cell-assembled with a color filter substrate, there is provided a Lead Pad zone. The Lead Pad zone mainly acts to add test signals for detection of electrical properties in the course of manufacturing the array substrate.
In general, a manufacturing process of the array substrate is divided into steps of, forming a gate metal layer, which includes a gate electrode and a gate line; forming a gate insulating layer and an amorphous silicon semiconductor layer; forming a source/drain metal layer, which includes a source electrode, a drain electrode and a data line; forming a passivation layer; forming a pixel electrode.
In the above process, as an integral, uninterrupted lead design structure is adopted at the Lead Pad zone, damage will be brought about to metal layers and an insulating layer when a cutting process is conducted on the array substrate, thereby generating tiny cracks. Therefore, with infiltration of water vapor and so on during use, the phenomenon that metals of the gate metal layer and the source/drain metal layer are corroded may occur.